21174321 has 24 divisors (see below), whose sum is σ = 33981120. Its totient is φ = 11680032.

The previous prime is 21174319. The next prime is 21174331. The reversal of 21174321 is 12347112.

It is not a de Polignac number, because 21174321 - 2¹ = 21174319 is a prime.

It is a super-2 number, since 2×21174321² = 896703739622082, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21174301) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1780 + ... + 6746.

It is an arithmetic number, because the mean of its divisors is an integer number (1415880).

Almost surely, 2^21174321 is an apocalyptic number.

21174321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21174321 is a deficient number, since it is larger than the sum of its proper divisors (12806799).

21174321 is a wasteful number, since it uses less digits than its factorization.

21174321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5013 (or 5006 counting only the distinct ones).

The product of its digits is 336, while the sum is 21.

The square root of 21174321 is about 4601.5563671436. The cubic root of 21174321 is about 276.6537093333.

The spelling of 21174321 in words is "twenty-one million, one hundred seventy-four thousand, three hundred twenty-one".